Tooth

Ancient whale tells tale of when baleen whales had teeth

36-million-year-old fossil belonged to oldest discovered member of group that includes humpbacks

Mystacodon skull
WHALE IN TRANSITION The skull of Mystacodon, a 36-million-year-old whale found in Peru, is an early relative of today’s baleen whales. Its skull (shown here) has a flattened snout and a mouth full of teeth, which baleen whales later lost.

A 36-million-year-old fossil skeleton is revealing a critical moment in the history of baleen whales: what happened when the ancestors of these modern-day filter feeders first began to distinguish themselves from their toothy, predatory predecessors. The fossil is the oldest known mysticete, a group that includes baleen whales, such as humpbacks, researchers report in the May 22 Current Biology.

Scientists have made predictions about what the first mysticetes might have looked like, but until now, haven’t had much fossil evidence to back up those ideas, says Nicholas Pyenson, a paleobiologist at the Smithsonian National Museum of Natural History in Washington, D.C. “Here, we have something we’ve been waiting for: a really old baleen whale ancestor.”

The earliest whales were predators with sharp teeth — a legacy carried on by today’s orcas, dolphins and other toothed whales. But at some point during whale history, the ancestors of modern mysticetes replaced teeth with baleen, fibrous plates that filter out small bits of food from seawater like a giant sieve. Such a huge lifestyle change didn’t happen overnight, though. And the new find, dubbed Mystacodon selenensis, shows the start of that transition, its discoverers say.

Mystacodon largely fits in well with what scientists have predicted from analyzing other whales, says Mark Uhen, a paleobiologist at George Mason University in Fairfax, Va. “It fleshes out this transition, rather than being something wacky and crazy we never thought of.”

Mystacodon was unearthed in a Peruvian desert by…

Best Money Tips: Natural Ways to Whiten Your Teeth

Welcome to Wise Bread’s Best Money Tips Roundup! Today we found articles natural ways to whiten your teeth, the best places for new dads to work, and ways to sell clothes for cash.

Top 5 Articles

Natural Ways to Whiten Your Teeth — The oil pulling method breaks down the toxins and bacteria that can build up on teeth and cause staining. [Nature Moms Blog]

The 20 best places for new dads to work — These companies have the best paternity leave policies, as well as flexible hours and telecommuting options. [AOL Finance]

5 Ways to Sell Clothes for Cash — If you want to reach more potential customers, consider selling your clothes online through sites like Swap.com, ThredUp, and Poshmark. [Flipping Income]

3 Important Tips to Keep in Mind When Exchanging Foreign Currency — Airport exchange rates…

Tooth Decay May Have Turned Lions into Man-Eaters

Looking for good motivation to brush and floss? Mammal experts say the infamous lions that killed dozens of rail workers in Kenya in 1898 may have been driven by dental disease. They published a report on the unfortunate beasts in the journal Scientific Reports.

There were only two of them, but the damage they did was both extensive and terrifying. “I could plainly hear them crunching the bones,” Lieutenant Colonel John Patterson wrote in his diary, “and the sound of their dreadful purring filled the air and rang in my ears afterwards.”

Patterson with one of the Tsavo lions. Image Credit: The Field Museum

Patterson eventually killed the lions, and their remains were preserved for scientific study. Today, the two skulls are kept in the collection of Chicago’s Field Museum so scientists can study them.

The Field Museum

Historians have long believed that the lions turned to human prey out of desperation when a famine eliminated their usual sources of food. If this was…

How the house mouse tamed itself

tiny mouse skull
The tiny molars in this skull help tell a tale of mice and men, and how humans transitioned from nomadic to sedentary lifestyles.

Got a mouse in the house? Blame yourself. Not your housekeeping, but your species. Humans never intended to live a mouse-friendly life. But as we moved into a settled life, some animals — including a few unassuming mice — settled in, too. In the process, their species prospered — and took over the world.

The rise and fall of the house mouse’s fortunes followed the stability and instability of the earliest human settlements, a new study shows. By analyzing teeth from ancient mice and comparing the results to modern rodents hanging out near partially settled groups, scientists show that when humans began to settle down, one mouse species seemed to follow. When those people moved on, another species moved in. The findings reveal that human settlement took place long before agriculture began, and that vermin didn’t require a big storehouse of grain to thrive off of us.

Between 15,000 and 11,000 years ago (a time called the Natufian period), people began to form small stone settlements in what is now Israel and Jordan. They were not yet farming or storing grain, but they were living in a single place for a season or two, and coming back to that place relatively often. Those early settlers changed the ecosystem of the world around them — presenting new opportunities for local flora and fauna.

Lior Weissbrod, an archaeologist at the University of Haifa in Israel, started his career wanting to search for clues to the history of animal-human relationships. He was especially interested in animal remains. But, he admits, mouse teeth weren’t exactly his first choice. “[At] the site I was going to work on, the remains of larger animals were already studied,” he says. “I was left with the small mammals.”

Small mammals have even smaller teeth. The largest mouse molars are only about 1 millimeter long. This meant a lot of time sifting dirt through very fine mesh for Weissbrod. He collected 372 mouse teeth from the dirt of five different archaeological sites in modern-day Israel and Jordan, with remains dating from 11,000 to 200,000 years ago. He gave the teeth to his colleague Thomas Cucchi of the National Museum of Natural History in Paris, who developed a technique to classify the mouse teeth by species based on tiny differences in their shape.

A mouse skull (middle) sits between a partial cat skull and an Israeli coin. A full mouse skull is only about the size of quarter, and one of its molars is only 1 millimeter long.

The first human…

Ancient dental plaque tells tales of Neandertal diet and disease

upper jaw from Neandertal
Calcified dental plaque from the upper jaw of a young Neandertal male from El Sidron cave in Spain reveals insights into his vegetarian diet and dental health problems.

Dental plaque preserved in fossilized teeth confirms that Neandertals were flexible eaters and may have self-medicated with an ancient equivalent of aspirin.

DNA recovered from calcified plaque on teeth from four Neandertal individuals suggest that those from the grasslands around Beligum’s Spy cave ate woolly rhinoceros and wild sheep, while their counterparts from the forested El Sidron cave in Spain consumed a menu of moss,…